This invention relates to a process for treating arrhythmias, and more particularly, to process for preventing or ameliorating arrhythmia by lengthening cardiac cell action potential duration and refractory period without beta-adrenergic blockade by administering an effective dose of dextrorotatory 4-(2-isopropylamino-1-hydroxyethyl)-methanesulfonanalide or a pharmaceutically acceptable acid addition salt thereof.
The racemic form of 4-(2-isopropylamino-1hydroxyethyl)-methanesulfonanilide, disclosed and claimed in Larsen, et al., U.S. Pat. No. 3,341,584, is a recognized beta-blocking agent known in the biological literature as sotalol or MJ 1999. Pharmacologically, beta-blocking compounds reduce sympathetic excitation of the heart and in this respect are considered antiarrhythmics.
Antiarrhythmic drugs are commonly divided into four classes according to their electrophysiological mode of action. Refer to N. Edvardsson, Current Therapeutic Research, 28, No. 1 Supplement, pages 113S-118S, July, 1980, and Keefe, et al., Drugs, 22, 363-400 (1981) for background information of classification first proposed by E. M. Vaughn Williams: classification of antiarrhythmic drugs, in "Symposium of Cardiac Arrhythmias," pages 449-472, Sandoe, et al., (Eds.) A. B. Astra, Soederlalje, Sweden (1970).